City police officers and federal agents converged on a Brooklyn neighborhood yesterday and arrested gun-toting drug dealers said to be so brazen that they fight each other in a sidewalk competition to sell crack cocaine.

Police arrested 25 people and raided seven houses, culminating a three-month undercover investigation at the Brooklyn Homes Projects. The four-square-block community of public housing and apartments was described by police as the most crime-ridden section in Brooklyn, which has a population of about 9,000.

In the past five months, police said, 48 armed robberies, 10 shootings and 76 assaults were reported at Brooklyn Homes housing project, where about 1,000 people live.

"The information we had was that the dealers would fight each other over who made the sale," said Police Commissioner Thomas C. Frazier.

"They would all run out, and the one to touch the car first got the sale. In one case, a guy who just made a sale got mugged. It was out of control."

Residents gathered at street corners and in yards to watch the afternoon sweep by 100 officers, including a federal task force of 45 Alcohol, Tobacco and Firearms investigators and a dozen U.S. Secret Service agents.

"It's a nice change," said Scott Wesley, 26, who lives in the 800 block of Stoll St., where two houses were raided.

His friend Michael Corporal, 32, who lives a block away, said his front door has been fired on. He also said he has bullet holes in both of his trucks and a wall of his house.

"You worry every time a round goes off," Mr. Corporal said. "You jump up and wonder where it went."

In addition to the houses raided on Stoll Street, police said they hit four houses in the 800 and 900 blocks of Jack St. and one house in the 900 block of Herndon Ave.

In the Herndon Avenue house, police said they confiscated 51 vials of suspected crack cocaine and a .357-caliber Magnum handgun. Police also said they found 109 bags and 68 vials of suspected cocaine in two other houses, as well as a police scanner programmed to the Southern District.

By 7:30 p.m. yesterday, police said they had arrested 13 of the 23 people charged before the raid in drug and gun warrants, as well as 12 others on drug charges. Several people taken into custody in front of reporters appeared calm -- and even comical -- as they were hauled into police vans.

"We will be home by tonight, baby," one man hollered, as he lay face down in his front yard, his hands cuffed behind him. "They got nothing. I'm sitting on my porch, and they locked me up for nothing."

But the police commissioner, who has overseen five other raids -- many much larger in scope then yesterday's -- disagreed.

"I'd bet you lunch he won't be out tonight," Mr. Frazier responded. "That's what they said on Greenmount, and six or seven months later, they are still in jail."

The March raid in the Midway neighborhood off Greenmount Avenue was the first sweep conducted by the new police commissioner, who has promised to rid street corners of drug dealers.

Mr. Frazier said that 44 of the 46 people arrested in that raid are still behind bars.

While yesterday's raid was not as big in scope as Operation Midway, Mr. Frazier said it would have the same impact for Brooklyn residents who lived among dealers selling cocaine from dusk to dawn.

Maj. Kathy Patek, the commander of the Southern District, said complaints from residents sparked the raid.

"This is one of the hottest drug corners in Brooklyn," she said, standing at Ninth and Jack streets. She then turned to watch federal ATF agents lock up a 16-year-old wanted on a drug warrant.

"He's one of our major dealers," she said. "We have a lot of young ones."